Magnetic chuck



April 15, 1930. J. M. WEYDELL Filed June 24, 1927 CJI Patented pr. 15, 1930 ar oFFiea JARL M. WEYDELL, OIF INDIANAPOLIS, INDIANA, ASSIGNOR OF ONE-HALF TO EDWARD E. STOUT MAGNETIC CHUCK Application led .Tune 24,

It is the object of my invention to produce a rotary magnetic chuck suitable for mounting on the rotatable spindle of a machine tool. More specifically, it is my object to produce such a chuck in which there are no moving parts to which current need be supplied, thus avoiding the necessity for collector rings to conduct current to a rotating coil.`

To accomplish the above object, I construct a chuck, the face of which, as is common, comprises a plurality of interspersed pole pieces of opposite magnetic polarity, and I mount on the chuck a member which carries an energizing coil and which is rotatable relative to the rest of the chuck in order that it may remain stationary while the chuck rotates.

The accompanying drawing illustrates my invention: Fig. 1 is a front elevation of the chuck; Fig. 2 is an axial section on the line 2-2 of Fig. 1; Fig. 3 is a front elevation of the chuck hub showing the radiating pole pieceswith which such hub is provided; Fig. 4 is an elevation of the chuck rim showing the inwardly projecting pole pieces which lie between those of the hub; Fig. 5 is a quarter-section of a chuck embodying a slight-ly modied form 01"' construction; and Fig. 6 is a fragmental section illustrating a inodilied form oil mounting for my chuck.

The rotating spindles of machine tools are usually provided with a threaded end 10 on which a chuck may be mounted. I provide my chuck with a collar 11, preferably nonmagnetic, having a screw-threaded axial hole adapted to be received on the end of the spindle 10, and I secure to this collar 11, as by means of screws 12, a plate 13 adapted to bear against the end of the spindle. To this plate is secured a stud 14 on the outer end of which the hub 15 of the chuck is mounted. Desirably, the stud is secured to the plate 13 and to the hub 15 by means of screw threads in order that the inner race 16 of an antifriction bearing 17 may be clamped between the hub 15 and the plate 13.

On the outer race 18 oi the anti-friction bearing 17, I mount a plate 19 preferably of non-magnetic material, such plate having secured to it an arm 2O adapted to bear against 192i'. seran No. 201,151.

some stationary part 21 of the machine tool to prevent rotation of the plate '19. A core 23 having an outwardly extending flange 24 is secured to the plate 19 as by means of screws 25 which pass through the plate 19 and into the flange 24. That end of the core 23 which is opposite the ange 24 is provided with screw threads adapted to be received within a collar 28, between which and the flange 24 a coil of wire 29 is clamped. The wire ends 30 of the coil 29 are connected to any suitable source of direct current through a reversing switch 31.

The outer end of the ch'uck hub 15 is provided with a plurality of radiating fingers 33 which serve as one set oli' poles for the chuck. The other set of poles for the chuck is provided by a plurality of lingers 34 which extend inward from the periphery oia shell 35, such shell being arranged to receive within it the coil 29 and the flange 24. Desirably, the shell is also deep enough to receive the stationary plate 19. The shell is secured in place by means of a plate 35 of non-magnetic material which lies against the back of the lingers 33 and 34 and is secured thereto as by means of screws 37. The spaces between the fingers 34 of the shell 35 are larger than the lingers 33 so that a space is provided between the two sets of lingers, such space being lled with any suitable non-magnetic material 38, as is customary.

The chuck may be so constructed that a relatively small air gap is provided between the core 23 and the hub 15 and between the coreilange 24 and the shell 35, only sufhcient space being needed at these points to insure that free rotation oit the chuck will not be interieredl with. Desirably, thelange 24 is thickened axially at its peripheral edge to provide a rim 40 which serves to increase the crosssectional area of the air gap across which the magnetic lines ci force pass from the core flange 24 to the shell 35.

vIn the modification ot my invention illustrated in 5, I make the core for the coil 29 partly solid and partly laminated, the construction otherwise being substantially the same as that shown in Figs. 1 to 4 inclusive.

The solid portion of the core comprises a hub l5 and a flange i6, the coil 29 being held in place between the flange #L6 and the screwthrcaded collar 28. interposed between the flange i6 and the supporting plate 19 are a plurality oi laminations of magnetic material through which the magnetic linesof force pass to or from the shell 35.

If desired, I may lighten the shell 35 by providing'it with a plurality of slots 48 which extend through its circumferential wall. In order that the chuck, if so constructed,imay provide a smooth outer surjace tending to minimize the chances ofaccident, I'provide a continuous band i9 which surrounds the shell 35 and covers the slots 48. Theslots are preferably so located that the metal between fthemisflocatedlin substantial alinement with f' the' fingers 34.

It is'not necessary that the rotating member onwhichmyfchuck is'mounted be a driving membeiz .In Figa() I have shown the chuck 'as carried'by'a rotatable shaft 5l vsupported .in bearings 52 andadapted to be driven from driving .shaft 53 which carries a pinion 54 :arranged to engage gear teeth on the shell 35.

In operation, my chuck is mounted on the spindle l0 by screwing-f the collar l1 thereonto. rrrilhe yarmrQO isthen brought into en- .gagement withv some stationary part of the machine vtool on `which the chuck is being used, thus'insuring that the plate 19 andthe i parts which it. carries will remain stationary, while the remainder or" the chuck is vfree to rotate. zTh-efworkis held against the aceof the chuck and the coil'29 energized by closing the-switchl. l/Vhen the spindle 10 rotates, the face and rim ofthe chuck rotate, carrying with them the work which is secured tothe 'tace of the chuck by the magnetic field produced bythe interspersed poles 33 and 34. rlFhecoil 29, during this rota-tion, remains, stationary, andl am thusv enabled to {avoid the necessityfor collector rings which would.berequired to supply current to the coil 29 ifsuch coil rotates with the remainder of the ohuck. Vhen the work is finished, the spindle l() is brought to rest, and the switch 41l-.isopen -Desirably, the 'switch 3l is so const-ructed that itfmay reverse the -flow of currentthrough the vcoil 29` in order to remove any resi'dualmagnetism which may tend to hold the-work in place on the chuck. This `reversal otcurrent need only be momentary.

A I claim as .my invention vl. A magnetic chuck, comprising a rotatable memberhaving two magnetically separate yfmagnetic portions, each of said magnetic ,i portionshaving poles spaced from the poles of the other portion, one of said magnetic porvtionsy having a :hub and the other a rim pro- 'vidin'g'an annular spacebetween them, a stav.tionar'y :magneticmember located in said an- ;Jnularispacefand in close proximity to and l :iinagnetically .between Said lhubiand rim, and

a stationary magnetizing coil in magnetizing relation to said .stationary magnetic member and to said magnetic portions.

2. A magnetic chuck, comprising a rotatable member having two magnetically separate magnetic portions, each of saidtmagnetic portions having poles spaced-fromathe .poles of the other portion, one of said magnetic portions having a hub and the other a rimfpro vi'ding an annular space'betweenthem,^^and a stationary maenetizing coil located in such annular space and in magnetizing relation to said magnetic portions.

3. .-A, magnetic :chuck comprising a rotatable part, a member carried by saidlpart and having two magnetically separate lmagnetic portions, each offsaid portions Ihaving kpoles spaced-from the pol ofthe otherportion, a

stationary member of non-mavnetic material supported from said rotatabl tionary magnetic member supported from said stationary'non-magnetic member, vand .a magnetizing coil in'magnetlzing relation to ysaid .stationary magneticfmember.

.4. A magnetic chuclnicomprising a r0tatany supported face-portion of magneticfmaterial, a second'iiace-portion 'alsoofA magnetic iat-erial, `a member oiy non-magnetic material for snpportingsaid secon d faceeportion; from `said first iaceportion whereby saidtwoifaceportions may rotate together, said member forming the sole support for id secondfaceportion,y anda stationary'magnetizingfcoil in magnetizing relation to said face-portions.

En witness whereof, I have hereunto set my hand at Indianapolis, `Indiana, this 15th. day of June, A. AD. yonethonsand nine hundred and twentyfseven.

JRLv M. l/VEYDELL.

e part, Va :sta-

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